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Purpose: This study aimed to investigate the temporal effects of ~1800 m altitude exposure and energy availability (EA) manipulation on resting metabolic rate (RMR). Methods: Twenty elite female race walkers underwent a 3-wk training camp at an altitude of ~1800 m. During the first 2 wk, athletes consumed a high EA (HEA) diet of 45 kcal·kg fat-free mass (FFM)−1·d−1. During the final week, half the athletes consumed a low EA (LEA) diet of 15 kcal·kg FFM−1·d−1, whereas the others continued on an HEA diet. Athletes followed individualized training plans throughout the study. To assess the effect of altitude on RMR, athletes in the HEA group had RMR measured at baseline (~580 m) before altitude exposure (Pre-alt), at 36 h (36h-alt), 2 wk (Wk2-alt), and 3 wk into altitude exposure (Wk3-alt), and at 36 h post-altitude exposure at ~580 m (36h-post). To assess the effect of LEA exposure on RMR while at altitude, athletes in the LEA group underwent RMR measurements at Pre-alt and before (Wk2-alt) and after the 7 d of LEA (Wk3-alt). Results: Compared with Pre-alt, the RMR of HEA athletes was increased at 36h-alt (+5.3% ± 3.1%; P = 0.026) and Wk2-alt (+4.9% ± 4.9%; P = 0.049), but was no longer elevated at Wk3-alt (+1.7% ± 4.2%; P = 0.850). The RMR of HEA athletes at 36h-post was lower than all timepoints at altitude (P < 0.05) but was not different from Pre-alt (−3.9% ± 7.2%; P = 0.124). The 7-d period of LEA exposure at altitude did not affect RMR (P = 0.347). Conclusions: RMR was transiently increased with ~1800-m altitude exposure in female athletes and was unaffected by short-term LEA. However, the altitude-induced increase was small (~25–75 kcal·d−1) and was unlikely to have clinically significant implications for daily energy requirements. [ABSTRACT FROM AUTHOR]

Purpose: To assess elite racewalkers' preparation strategies, knowledge, and general practices for competition in the heat and their health status during the World Athletics Race Walking Teams Championships (WRW) Muscat 2022. Methods: Sixty-six elite racewalkers (male: n = 42; mean age = 25.8 y) completed an online survey prior to WRW Muscat 2022. Athletes were grouped by sex (males vs females) and climate (self-reported) they live/trained in (hot vs temperate/cold), with differences/relationships between groups assessed. Relationships between ranking (medalist/top 10 vs nonmedalist/nontop 10) and precompetition use of heat acclimation/acclimatization (HA) were assessed. Results: All surveyed medalists (n = 4) implemented, and top 10 finishers were more likely to report using (P =.049; OR = 0.25; 95% CI, 0.06%–1%), HA before the championships. Forty-three percent of athletes did not complete specific HA training. Females (8% [males 31%]) were less likely to have measured core temperature (P =.049; OR = 0.2; 95% CI, 0.041–0.99) and more likely to not know expected conditions in Muscat (42% vs 14%; P =.016; OR = 4.3; 95% CI, 1%–14%) or what wet bulb globe temperature is (83% vs 55%; P =.024; OR = 4.1; 95% CI, 1%–14%). Conclusions: Athletes who implemented HA before the championships tended to place better than those who did not. Forty-three percent of athletes did not prepare for the expected hot conditions at the WRW Muscat 2022, primarily attributed to challenges in accessing and/or cost of equipment/facilities for HA strategies. Further efforts to bridge the gap between research and practice in this elite sport are needed, particularly in female athletes. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effects of a high-carbohydrate diet (HCHO), periodized-carbohydrate (CHO) diet (PCHO), and ketogenic low-CHO high-fat diet (LCHF) on training capacity. Methods: Elite male racewalkers completed 3 weeks of periodic training while adhering to their dietary intervention. Twenty-nine data sets were collected from 21 athletes. Each week, 6 mandatory training sessions were completed, with additional sessions performed at the athlete's discretion. Mandatory sessions included an interval session (10 × 1-km efforts on a 6-min cycle), tempo session (14 km with a 450-m elevation gain), 2 long walks (25–40 km), and 2 easy walks (8–12 km) where "sleep-low" and "train-low" dietary strategies were employed for PCHO. Racewalking speed, heart rate, rating of perceived exhaustion, and blood metabolites were collected around key sessions. Results: LCHF covered less total distance than HCHO and PCHO (P <.001); however, no differences in training load between groups were evident (P =.285). During the interval sessions, walking speed was slower in LCHF (P =.001), equating to a 2.8% and 5.6% faster speed in HCHO and PCHO, respectively. LCHF was also 3.2% slower in completing the tempo session than HCHO and PCHO (P =.001). Heart rate was higher (P =.002) and lactate concentrations were lower (P <.001) in LCHF compared to other groups, despite slower walking speeds during the interval session. No between-groups differences in rating of perceived exhaustion were evident (P =.077). Conclusion: Athletes adhering to an LCHF diet showed impaired training capacity relative to their high-CHO-supported counterparts, completing lower training volumes at slower speeds, with higher heart rates. [ABSTRACT FROM AUTHOR]

Current guidelines for prolonged altitude exposure suggest altitude levels ranging from 2000 to 2500 m to optimize an increase in total hemoglobin mass (Hbmass). However, natural low altitude locations (<2000 m) remain popular, highlighting the interest to investigate any possible benefit of low altitude camps for endurance athletes. Ten elite racewalkers (4 women and 6 men) underwent a 4‐week "live high‐train high" (LHTH) camp at an altitude of 1720 m (PIO2 = 121 mmHg; 20.1°C; 67% relative humidity [RH]), followed by a 3‐week tapering phase (20 m; PIO2 = 150 mmHg; 28.3°C; 53% RH) in preparation for the World Athletics Championships (WC). Venous blood samples were withdrawn weekly during the entire observation period. In addition, blood volumes were determined weekly by carbon monoxide rebreathing during altitude exposure and 2 weeks after return to sea level. High‐level performances were achieved at the WC (five placings among the Top 10 WC races and three all‐time career personal bests). A slight but significant increase in absolute (+1.7%, p = 0.03) and relative Hbmass (+2.3%, p = 0.02) was observed after 4‐week LHTH. In addition, as usually observed during LHTH protocols, weekly training distance (+28%, p = 0.02) and duration (+30%, p = 0.04) significantly increased during altitude compared to the pre‐LHTH period. Therefore, although direct causation cannot be inferred, these results suggest that the combination of increased training load at low altitudes with a subsequent tapering period in a warm environment is a suitable competition‐preparation strategy for elite endurance athletes. Highlights: Despite current guidelines for prolonged altitude exposure, natural low altitude locations (<2000 m) remain popular among elite endurance athletes, highlighting the interest to investigate any possible benefit of low altitude camps.This study reports that elite racewalkers achieved a modest but significant increase in Hbmass after a 4‐week LHTH camp at an altitude of 1720 m. Furthermore, this intervention led to performance success at the subsequent World Athletics Championships.The combination of an increased training load while exposed to low altitude is suggested as a valuable competition preparation strategy for elite endurance athletes. [ABSTRACT FROM AUTHOR]

This study implemented a 2-week high carbohydrate (CHO) diet intended to maximize CHO oxidation rates and examined the iron-regulatory response to a 26-km race walking effort. Twenty international-level, male race walkers were assigned to either a novel high CHO diet (MAX = 10 g/kg body mass CHO daily) inclusive of gut-training strategies, or a moderate CHO control diet (CON = 6 g/kg body mass CHO daily) for a 2-week training period. The athletes completed a 26-km race walking test protocol before and after the dietary intervention. Venous blood samples were collected pre-, post-, and 3 hr postexercise and measured for serum ferritin, interleukin-6, and hepcidin-25 concentrations. Similar decreases in serum ferritin (17–23%) occurred postintervention in MAX and CON. At the baseline, CON had a greater postexercise increase in interleukin-6 levels after 26 km of walking (20.1-fold, 95% CI [9.2, 35.7]) compared with MAX (10.2-fold, 95% CI [3.7, 18.7]). A similar finding was evident for hepcidin levels 3 hr postexercise (CON = 10.8-fold, 95% CI [4.8, 21.2]; MAX = 8.8-fold, 95% CI [3.9, 16.4]). Postintervention, there were no substantial differences in the interleukin-6 response (CON = 13.6-fold, 95% CI [9.2, 20.5]; MAX = 11.2-fold, 95% CI [6.5, 21.3]) or hepcidin levels (CON = 7.1-fold, 95% CI [2.1, 15.4]; MAX = 6.3-fold, 95% CI [1.8, 14.6]) between the dietary groups. Higher resting serum ferritin (p =.004) and hotter trial ambient temperatures (p =.014) were associated with greater hepcidin levels 3 hr postexercise. Very high CHO diets employed by endurance athletes to increase CHO oxidation have little impact on iron regulation in elite athletes. It appears that variations in serum ferritin concentration and ambient temperature, rather than dietary CHO, are associated with increased hepcidin concentrations 3 hr postexercise. [ABSTRACT FROM AUTHOR]

Purpose: To quantify, for an elite-level racewalker, altitude training, heat acclimation and acclimatization, physiological data, and race performance from January 2007 to August 2008. Methods: The participant performed 7 blocks of altitude training: 2 "live high:train high" blocks at 1380 m (total = 22 d) and 5 simulated "live high:train low" blocks at 3000 m/600 m (total = 98 d). Prior to the 2007 World Championships and the 2008 Olympic Games, 2 heat-acclimation blocks of ~6 weeks were performed (1 session/week), with ∼2 weeks of heat acclimatization completed immediately prior to each 20-km event. Results: During the observation period, physiological testing included maximal oxygen uptake (VO2max, mL·kg−1·min−1), walking speed (km·h−1) at 4 mmol·L−1 blood lactate concentration [La−], body mass (kg), and hemoglobin mass (g), and 12 × 20-km races and 2 × 50-km races were performed. The highest VO2max was 67.0 mL·kg−1·min−1 (August 2007), which improved 3.1% from the first measurement (64.9 mL·kg−1·min−1, June 2007). The highest percentage change in any physiological variable was 7.1%, for 4 mmol·L−1 [La−] walking speed, improving from 14.1 (June 2007) to 15.1 km·h−1 (August 2007). Personal-best times for 20 km improved from (hh:mm:ss) 1:21:36 to 1:19:41 (2.4%) and from 3:55:08 to 3:39:27 (7.1%) in the 50-km event. The participant won Olympic bronze and silver medals in the 20- and 50-km, respectively. Conclusions: Elite racewalkers who regularly perform altitude training may benefit from periodized heat acclimation and acclimatization prior to major international competitions in the heat. [ABSTRACT FROM AUTHOR]

Purpose: The core temperature responses during exercise and effects of different cooling strategies on endurance performance under heat stress have been investigated in recreational athletes. This investigation aimed to determine peak rectal temperatures during elite racewalking competitions and to detail any cooling strategies used. Methods: Rectal temperature was measured in 14 heat-adapted elite/preelite race walkers (9 females) via a telemetric capsule across 4 outdoor events, including the 2018 Commonwealth Games (race 1: 20 km, 25°C, 74% relative humidity [RH], n = 2) and 3 International Association of Athletics Federations-sanctioned 10-km events (race 2: 19°C, 34% RH, n = 2; race 3: 29°C, 47% RH, n = 14; and race 4: 23°C, 72% RH, n = 11). All athletes completed race 3, and a subsample completed the other events. Their use of cooling strategies and symptoms of heat illness were determined. Results: Peak rectal temperatures >40°C were observed in all events. The highest rectal temperature observed during an event was 41.2°C. These high rectal temperatures were observed without concomitant heat illness, with the exception of cramping in one athlete during race 1. The rectal temperatures tended to reach a steady state in the second half of the 20-km event, but no steady state was observed in the 10-km events. The athletes used cooling strategies in race 1 only, implementing different combinations of cold-water immersion, ice-slurry ingestion, ice-towel application, ice-vest application, and facial water spraying. Conclusions: Elite/preelite race walkers experience rectal temperatures >40°C during competition despite only moderate-warm conditions, and even when precooling and midcooling strategies are applied. [ABSTRACT FROM AUTHOR]

Flat jockeys in Great Britain (GB) are classified as apprentices if they are aged less than 26 years and/or have ridden less than 95 winners. To gain experience, apprentices are allocated a weight allowance of up to 7 lb (3.2 kg). Given that there is no off-season in GB flat horseracing, jockeys are required to maintain their racing weight all year round. In light of recent work determining that current apprentices are considerably heavier than previous generations and that smaller increases have been made in the minimum weight, the aim of this study was to assess if the minimum weight in GB was achievable. To make the minimum weight (50.8 kg) with the maximal weight allowance requires a body mass of ∼46.6 kg while maintaining a fat mass >2.5 kg (the lowest fat mass previously reported in weight-restricted males). Thirty-two male apprentice jockeys were assessed for body composition using dual-energy X-ray absorptiometry. The mean (SD) total mass and fat mass were 56 (2.9) kg and 7.2 (1.8) kg, respectively. Given that the lowest theoretical body mass for this group was 51.2 (2.3) kg, only one of 32 jockeys was deemed feasible to achieve the minimum weight with their current weight allowance and maintaining fat mass >2.5 kg. Furthermore, urine osmolality of 780 (260) mOsmol/L was seen, with 22 (out of 32) jockeys classed as dehydrated (>700 mOsmols/L), indicating that body mass would be higher when euhydrated. Additionally, we observed that within new apprentice jockeys licensed during this study (N = 41), only one jockey was able to achieve the minimum weight. To facilitate the goal of achieving race weight with minimal disruptions to well-being, the authors' data suggest that the minimum weight for GB apprentices should be raised. [ABSTRACT FROM AUTHOR]

During the nineteenth century, both medicine and sport were transitioning into recognizably modern identities but no formal relationship between the two existed. It has been suggested that the medical profession had little engagement with sport during this period. One sport that was particularly popular during the nineteenth century was pedestrianism in which athletes performed a range of endurance walking challenges for money and fame. While it has previously been recognized that some medical practitioners were involved in the support of pedestrian athletes, to date there has been no formal evaluation of the magnitude or nature of that involvement. Hence there is a potential that the contribution of medicine to aspects of sport in the nineteenth century may have been under-recognized. Using predominantly contemporaneous reports, this paper investigates the medical support utilized by nineteenth century professional pedestrians. It illustrates that during a period in which medicine underwent a seismic paradigm shift, some doctors were actively involved in both the clinical support and scientific assessment of pedestrians. In so doing, the role that nineteenth century medical practitioners played in supporting endurance pedestrians is clarified and a gap in the literature addressed pertaining to the nineteenth century interactions of medicine and sport. [ABSTRACT FROM AUTHOR]

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The aim of this study was to investigate the role of energy cost in locomotion, specifically the rate of perceived exertion and movement variability in gait transition for eight race walkers (RW) and seven nonrace walkers (NRW). We hypothesized that a group of correlated variables could serve as combined triggers. Participants performed a preferred transition speed (PTS) test, exhibiting a higher PTS for RW (10.35 ± 0.28 km/hr) than for NRW (7.07 ± 0.69 km/hr), because RW engaged in race walking before switching to running. None of the variables increased before transition and dropped in PTS, which challenged the hypothesis of a unique transition variable in gait transitions. Principal component analysis showed that combined hip angle variability and rate of perceived exertion could determine gait transitions in elite RW and NRW. Thus, human gait transition may be triggered by a pool of determinant variables, rather than by a single factor. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of natural altitude training (NAT) and simulated (SIM) live high:train low altitude training on road-race walking performance (min), as well as treadmill threshold walking speed (km·h−1) at 4 mmol·L−1 and maximal oxygen consumption, at 1380 m. Methods: Twenty-two elite-level male (n = 15) and female (n = 7) race walkers completed 14 d of NAT at 1380 m (n = 7), SIM live high:train low at 3000:600 m (n = 7), or control conditions (600-m altitude; CON, n = 8). All preintervention and postintervention testing procedures were conducted at 1380 m and consisted of an incremental treadmill test, completed prior to a 5 × 2-km road-race walking performance test. Differences between groups were analyzed via mixed-model analysis of variance and magnitude-based inferences, with a substantial change detected with >75% likelihood of exceeding the smallest worthwhile change. Results: The improvement in total performance time for the 5 × 2-km test in NAT was not substantially different from SIM but was substantially greater (85% likely) than CON. The improvement in percentage decrement in the 5 × 2-km performance test in NAT was greater than in both SIM (93% likely) and CON (93% likely). The increase in maximal oxygen consumption was substantially greater (91% likely) in NAT than in SIM. Improvement in threshold walking speed was substantially greater than CON for both SIM (91% likely) and NAT (90% likely). Conclusions: Both NAT and SIM may allow athletes to achieve reasonable acclimation prior to competition at low altitude. [ABSTRACT FROM AUTHOR]

Distance events in Athletics include cross country, 10,000-m track race, half-marathon and marathon road races, and 20- and 50-km race walking events over different terrain and environmental conditions. Race times for elite performers span ∼26 min to >4 hr, with key factors for success being a high aerobic power, the ability to exercise at a large fraction of this power, and high running/walking economy. Nutrition-related contributors include body mass and anthropometry, capacity to use fuels, particularly carbohydrate (CHO) to produce adenosine triphosphate economically over the duration of the event, and maintenance of reasonable hydration status in the face of sweat losses induced by exercise intensity and the environment. Race nutrition strategies include CHO-rich eating in the hours per days prior to the event to store glycogen in amounts sufficient for event fuel needs, and in some cases, in-race consumption of CHO and fluid to offset event losses. Beneficial CHO intakes range from small amounts, including mouth rinsing, in the case of shorter events to high rates of intake (75–90 g/hr) in the longest races. A personalized and practiced race nutrition plan should balance the benefits of fluid and CHO consumed within practical opportunities, against the time, cost, and risk of gut discomfort. In hot environments, prerace hyperhydration or cooling strategies may provide a small but useful offset to the accrued thermal challenge and fluid deficit. Sports foods (drinks, gels, etc.) may assist in meeting training/race nutrition plans, with caffeine, and, perhaps nitrate being used as evidence-based performance supplements. [ABSTRACT FROM AUTHOR]

Treadmill training is useful for racewalking training; however, it may affect gait characteristics and lead to non-legal techniques. The aim of this study was to determine the kinematic differences between treadmill and overground conditions during racewalking at different speeds. Twenty-two elite racewalkers participated in this study. They racewalked under treadmill and overground conditions at high and medium speeds. A 12-camera motion analysis system was used to record the racewalking trials. Significant condition by speed interactions were detected in step frequency and pelvis rotation angle; step frequency decreased while pelvis rotation angle increased from overground to treadmill conditions at high speed. Compared to overground conditions, racewalkers decreased the ankle dorsiflexion angle at heel strike and increased hip flexion, shoulder hyperextension, and elbow flexion angles at heel strike and hip and shoulder extension angles at toe-off under treadmill conditions. Compared to medium speed, racewalkers decreased the contact time, hip flexion, and shoulder hyperextension at heel strike, and ankle plantarflexion and shoulder extension angles at toe-off, and increased flight time, step length, and elbow flexion angle at heel strike at high speed. Several kinematic differences during racewalking were detected between treadmill and overground conditions, with more differences detected at high speed, indicating that treadmill racewalking, especially at high speed, has different gait characteristics. However, no differences were detected in flight time and knee angle under treadmill conditions compared to overground conditions, indicating that racewalking on a treadmill does not increase the risk of disqualification. [ABSTRACT FROM AUTHOR]

The authors describe the implementation of a 3-week dietary intervention in elite race walkers at the Australian Institute of Sport, with a focus on the resources and strategies needed to accomplish a complex study of this scale. Interventions involved: traditional guidelines of high carbohydrate (CHO) availability for all training sessions; a periodized CHO diet which integrated sessions with low and high CHO availability within the same total CHO intake; and a ketogenic low-CHO high-fat diet. Seven-day menus and recipes were constructed for a communal eating setting to meet nutritional goals as well as individualized food preferences and special needs. Menus also included nutrition support before, during, and after exercise. Daily monitoring, via observation and food checklists, showed that energy and macronutrient targets were achieved. Diets were matched for energy (∼14.8 MJ/d) and protein (∼2.1 g·kg−1·day−1) and achieved desired differences for fat and CHO, with high CHO availability and periodized CHO availability: CHO = 8.5 g·kg−1·day−1, 60% energy, fat = 20% of energy and low-CHO high-fat diet: 0.5 g·kg−1·day−1 CHO, fat = 78% energy. There were no differences in micronutrient intake or density between the high CHO availability and periodized CHO availability diets; however, the micronutrient density of the low-CHO high-fat diet was significantly lower. Daily food costs per athlete were similar for each diet (∼AU$ 27 ± 10). Successful implementation and monitoring of dietary interventions in sports nutrition research of the scale of the present study require meticulous planning and the expertise of chefs and sports dietitians. Different approaches to sports nutrition support raise practical challenges around cost, micronutrient density, accommodation of special needs, and sustainability. [ABSTRACT FROM AUTHOR]

Race walkers must conform to a unique gait pattern with no visible loss of contact with the ground. However, how the gait pattern affects the race walking economy is unclear. We investigated the energy cost (amount of energy spent per distance unit) at different race walking velocities and over a 25 km hybrid walk. Twenty-one international-level male race walkers ( V ˙ O2peak 63.8 ± 4.3 ml kg−1 min−1, age 31 ± 5 y, body mass 68.1 ± 7.0 kg) performed an incremental treadmill test consisting of 4 × 4 min submaximal stages with 1 km h−1 increments, and a 25 km submaximal hybrid walk (treadmill-overground) on separate days. Energy cost was measured continuously during the submaximal test and at km 0–1, 6–7, 12–13, 18–19, 23–24 of the 25 km hybrid walk. The CRW was similar across the four submaximal stages where half the athletes completed them at a higher (1 km h−1) absolute velocity (−0.01–0.15 ± ∼0.65); range of standardised differences ±90% CL, with a tendency for higher performing athletes to have a lower CRW when this was analysed during absolute race walking velocities of 12, 13 and 14 km−1 for the entire cohort (0.46–0.49 ± ∼0.67). There was no substantial change in CRW from the start to the end of the 25 km walk for the entire cohort (0.08 ± 2.2; standardised change ±90% CL). Elite race walkers are characterised by having a similar energy cost among athletes who perform at the same relative exercise intensity, and substantially higher energetics than counterpart elite endurance runners. [ABSTRACT FROM AUTHOR]

Contemporary nutrition guidelines promote a variety of periodized and time-sensitive recommendations, but current information regarding the knowledge and practice of these strategies among world-class athletes is limited. The aim of this study was to investigate this theme by implementing a questionnaire on dietary periodization practices in national/international level female (n = 27) and male (n = 21) middle- and long-distance runners/race-walkers. The questionnaire aimed to gain information on between and within-day dietary choices, as well as timing of pre- and posttraining meals and practices of training with low or high carbohydrate (CHO) availability. Data are shown as percentage (%) of all athletes, with differences in responses between subgroups (sex or event) shown as Chi-square χ² when p < .05. Nearly two-thirds of all athletes reported that they aim to eat more food on, or after, hard training days. Most athletes said they focus on adequate fueling (96%) and adequate CHO and protein (PRO) recovery (87%) around key sessions. Twenty-six percent of athletes (11% of middle vs 42% of long-distance athletes [χ² (1, n = 46) = 4.308, p = .038, phi = 0.3])) reported to undertake training in the fasted state, while 11% said they periodically restrict CHO intake, with 30% ingesting CHO during training sessions. Our findings show that elite endurance athletes appear to execute pre- and post-key session nutrition recovery recommendations. However, very few athletes deliberately undertake some contemporary dietary periodization approaches, such as training in the fasted state or periodically restricting CHO intake. This study suggests mismatches between athlete practice and current and developing sports nutrition guidelines. [ABSTRACT FROM AUTHOR]

We investigated one week of dietary microperiodization in elite female (n = 23) and male (n = 15) runners and race-walkers by examining the frequency of training sessions and recovery periods conducted with recommended carbohydrate (CHO) and protein availability. Food and training diaries were recorded in relation to HARD (intense or >90min sessions; KEY) versus RECOVERY days (other-than KEY sessions; EASY). The targets for amount and timing of CHO and protein around KEY sessions were based on current nutrition recommendations. Relative daily energy and CHo intake was significantly (p < .05) higher in males (224 ± 26 kJ/kg/d, 7.3 ± 1.4 g/kg/d CHO) than females (204 ± 29 kJ/kg/d, 6.2 ± 1.1 g/kg/d CHO) on HARD days. However, when adjusted for training volume (km), there was no sex-based difference in CHO intake daily (HARD: 0.42 ± 0.14 vs 0.39 ± 0.15 g/kg/km). Females appeared to periodize energy and protein intake with greater intakes on HARD training days (204 ± 29 vs 187 ± 35 kJ/kg/d, p = .004; 2.0 ± 0.3 vs 1.9 ± 0.3 g/kg/d protein, p = .013), while males did not periodize intakes. Females showed a pattern of periodization of postexercise CHO for KEY vs EASY (0.9 ± 0.4 vs 0.5 ± 0.3 g/kg; p < .05) while males had higher intakes but only modest periodization (1.3 ± 0.9 vs 1.0 ± 0.4; p = .32). There was only modest evidence from female athletes of systematic microperiodization of eating patterns to meet contemporary sports nutrition guidelines. While this pattern of periodization was absent in males, in general they consumed more energy and CHO daily and around training sessions compared with females. Elite endurance athletes do not seem to systematically follow the most recent sports nutrition guidelines of periodized nutrition. [ABSTRACT FROM AUTHOR]

The current study analysed the pacing behaviour of athletes competing in the middle-long track event finals of the IAAF Under 18 and Under 20 World Championships between 2015 and 2018. Official finishing times, 1000-m split times and positioning data of 116 female and 153 male athletes, competing in the middle-long distance running (3000 m, 5000 m and 10,000 m) and race walking (5000 m and 10,000 m) events, were gathered. Repeated measures analysis of variance, with 1000-m speed as within-subjects factor and final ranking (medallist, Top 8 or Top 12, rest of the field) as between-subjects factor, was performed to compare the pacing behaviour between athletes. Positioning of the athletes was analysed by Kendall tau-b (Tb) correlation between the intermediate position and final position. Overall, medallists increased their speed throughout a race, with the exception of the 5000 m running event, in which a parabolic pacing behaviour was exhibited. The 1000-m segment in which a significant (P > 0.05) difference in speed was exhibited between differently ranked athletes coincided with a strong (Tb> 0.7) correlation between intermediate and final positioning. These combined results point towards a separation between the athletes during the race, as the Top 8 or Top 12 and the rest of the field are unable to match the speed of the medallists. The distance, discipline, sex, age category and behaviour of competitors all influence the pacing behaviour of young track athletes during international level competition, emphasising the importance and complexity of developing adequate pacing behaviour in track athletes. The distribution of effort over an exercise task (i.e. pacing) is an important factor in endurance exercise competition. The pacing behaviour of athletes is determined by many aspects, such as the biomechanical characteristics of the task, the exercise environment and the age of the athlete Sport specific competition data from youth athlete sports events can provide insight into the pacing behaviour of developing athletes. These insights could assist in the optimalisation of the development of pacing behaviour of young athletes in the future. The current study analysed the 1000-m split times and positioning data of athletes competing in the running (3000 m, 5000 m and 10,000) and racewalking (5000 m and 10,000m) finals of the U18 and U20 IAAF world-championship. The difference in final ranking impacted the pacing behaviour of the athletes, with the medallists increasing their speed throughout the race and the other athletes separating from the medallists either early (rest of field) or later in the race (Top 8 or Top 12 athletes). [ABSTRACT FROM AUTHOR]

Background: The pacing strategy of endurance athletes has been well investigated in previous articles. However, few studies have compared the influence of sex, distance and performance level on the pacing strategy in race walkers. Aims: To compare the influence of sex, distance and performance levels on pacing strategies in race walking competitions. Methods: Thirty-four highly trained athletes (16 male 23.6 ± 7.4, 18 female 23.7 ± 7.0 years old) were recruited. The speed in km.h−1 was calculated, and later, normalized by the percentage of the maximum speed (%max). The pacing strategy (%max) were divided into start, middle and end phases and compared between sexes, distances and performance levels. Results: There was no relationship between the phases according to sex (F(2) = 0.06, p =.94, pn2 < 0.01) and distance (F(2) = 1.89, p = 0.16, pn2 = 0.05). There was an effect between phases and performance levels (F(4) = 2.94, p = 0.03, pn2 = 0.16), indicating that the medallists were more able to maintain the starting speed compared to non-medallists. Sex of the race walkers and race distance did not influence the pacing strategy. Conclusions: In summary, medallist athletes maintained their starting speed in the race, which is not performed by non-medallists, that decreased the speed during middle and end phase of the race. Evenly paced pacing strategy, with a careful starting speed can increase the possibility of success during race walking competitions. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. The consumption of a ketogenic low-carbohydrate (CHO), high-fat (LCHF) diet increases skeletal muscle fat utilization but impairs exercise economy. Whether the concomitant increase in circulating endogenous ketone bodies (KB) alters the capacity to metabolize exogenous ketone supplements such as the popular ketone monoester is unknown. Purpose: This study aimed to determine if LCHF and ketone ester (KE) supplementation can synergistically alter exercise metabolism and improve performance. Methods: Elite race walkers (n = 18, 15 males and 3 females; V˙O2peak, 62 ± 6 mL·min−1·kg−1) undertook a four-stage exercise economy test and real-life 10,000-m race before and after a 5-d isoenergetic high-CHO (HCHO, ~60%–65% fat; CHO, 20% fat; n = 9) or LCHF (75%–80% fat, <50 g·d−1 CHO, n = 9) diet. The LCHF group performed additional economy tests before and after diet after supplementation with 573 mg·kg−1 body mass KE (HVMN; HVMN Inc., San Francisco, CA), which was also consumed for race 2. Results: The oxygen cost of exercise (relative V˙O2, mL·min−1·kg−1) increased across all four stages after LCHF (P < 0.005). This occurred in association with increased fat oxidation rates, with a reciprocal decrease in CHO oxidation (P < 0.001). Substrate utilization in the HCHO group remained unaltered. The consumption of KE before the LCHF diet increased circulating KB (P < 0.05), peaking at 3.2 ± 0.6 mM, but did not alter V˙O2 or RER. LCHF diet elevated resting circulating KB (0.3 ± 0.1 vs 0.1 ± 0.1 mM), but concentrations after supplementation did not differ from the earlier ketone trial. Critically, race performance was impaired by ~6% (P < 0.0001) relative to baseline in the LCHF group but was unaltered in HCHO. Conclusion: Despite elevating endogenous KB production, an LCHF diet does not augment the metabolic responses to KE supplementation and negatively affects race performance. [ABSTRACT FROM AUTHOR]

The Theory of Planned Behavior (TPB) has been extensively used in predictive studies, but there have been considerably fewer experimental tests of the theory. One reason for this is that the guidance on developing concrete intervention strategies from the abstract theory is vague, and there are few exemplars of how to do this. The aim of this article is to provide such an exemplar. The development of an intervention to increase walking in the general public is described, based on the TPB, extended to include postvolitional processes. Identification of target constructs, elicitation of key salient beliefs underpinning these constructs, selection of appropriate behavior change techniques, and technique refinement. Each step is based on available evidence and consistent with theory. Perceived behavioral control (PBC) was identified as the key determinant of walking intentions, with an "intention-behavior gap" noted. A brief intervention was developed, using techniques to increase PBC by rehearsal of previous successful performance of behavior, along with planning techniques to translate motivation into behavior. This systematic approach taken should provide a model for others. The intervention has demonstrated efficacy in producing large changes in objectively measured walking behavior, in 2 separate evaluations reported elsewhere. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to describe the pacing profiles used by racewalkers competing in IAAF World Championships. Methods: The times for each 5-km segment were obtained for 225 men competing over 20 km, 214 women competing over 20 km, and 232 men competing over 50 km, of whom 49 did not finish. Athletes were grouped based on finishing position (for medalists) or finishing time. Results: Different pacing profiles were used by athletes grouped by finishing time, with 20-km medalists using negative pacing and those finishing within 5% of the winning time matching the medalists' early pace but failing to maintain it. Lower-placed 20-km athletes tended to start more quickly relative to personal-best pace and experienced significant decreases in pace later. Across all competitions, the fastest finishers started the slowest relative to previous best performance. All 50-km athletes slowed toward the finish, but lower-placed finishers tended to decrease pace earlier (with up to 60% of the race remaining). After halfway in the 50-km, 8 of the 15 athletes who had a 5-km split more than 15% slower than the previous split dropped out. Conclusions: The negative pacing profile used by 20-km medalists required the ability to start fast and maintain this pace, and similarly paced training may be beneficial in race preparation. Over 50 km, the tactic of starting slower than personal-best pace was generally less risky; nonetheless, any chosen pacing strategy should be based on individual strengths. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse changes in gait variability and symmetry with increasing speed in race walkers. Eighteen international athletes race walked on an instrumented treadmill at speeds of 11, 12, 13 and 14 km·h−1 in a randomised order for 3 min each. Spatiotemporal and ground reaction force data were recorded for 30 s at each speed. Gait variability was measured using median absolute deviation and inter-leg symmetry was measured using the symmetry angle. There was an overall effect of speed on all absolute values except push-off force, but symmetry and variability (except flight time) did not change with increased speed, step length and step frequency. Most athletes were asymmetrical for at least one variable, but none was asymmetrical for more than half of the variables measured. Therefore, being asymmetrical or having higher variability (<5%) in a few variables is normal. Taking all findings together, practitioners should exercise caution when deciding on the need for corrective interventions and should not be concerned that increasing gait speed could increase injury risk through changes to athletes' asymmetry. Race walking coaches should test at competition speeds to ensure that flight times, and any variability or asymmetry, are measured appropriately. [ABSTRACT FROM AUTHOR]

Background: Self-selection--whether individuals inclined to walk more seek to live in walkable environments--must be accounted for when studying built environment infuences on walking. The way neighborhoods are marketed to future residents has the potential to sway residential location choice, and may consequently affect measures of self-selection related to location preferences. We assessed how walking opportunities are promoted to potential buyers, by examining walkability attributes in marketing materials for housing developments. Methods: A content analysis of marketing materials for 32 new housing developments in Perth, Australia was undertaken, to assess how walking was promoted in the text and pictures. Housing developments designed to be pedestrian-friendly (LDs) were compared with conventional developments (CDs). Results: Compared with CDs, LD marketing materials had signifcantly more references to 'public transport,' 'small home sites,' 'walkable parks/open space,' 'ease of cycling,' 'safe environment,' and 'boardwalks.' Other walkability attributes approached signifcance. Conclusion: Findings suggest the way neighborhoods are marketed may contribute to self-reported reasons for choosing particular neighborhoods, especially when attributes are not present at the time of purchase. The marketing of housing developments may be an important factor to consider when measuring self-selection, and its infuence on the built environment and walking relationship. [ABSTRACT FROM AUTHOR]

Background: Although many Japanese older adults spend more than an hour each day walking for exercise, the intensity is often lower than the minimum level associated with various health benefits. The purpose of this study was to evaluate the efficacy of a lifestyle physical activity intervention on improving quantity and quality of daily physical activity (DPA) as well as cardiorespiratory endurance in community- dwelling older women. Methods: 68 women (60-78 yr of age) were randomly assigned to either a lifestyle physical activity intervention group (LIFE) or control group. During the 12-wk intervention, feedback based on accelerometer DPA data (number of daily steps (STEPS) and time spent performing daily moderate intensity physical activity (MPA) was provided to each participant in LIFE every two weeks. Cardiorespiratory endurance was evaluated using the 12-Minute Walk Test (12- MW). Results: Following the 12-wk intervention, significant group interactions were observed for STEPS, MPA, and cardiorespiratory endurance. LIFE increased STEPS by 16%, MPA by 53%, and the distance walked during the 12-MW by 10%. Conclusions: Promotion of DPA using accelerometers can significantly improve quantity and quality of daily physical activity as well as cardiorespiratory endurance in older women. [ABSTRACT FROM AUTHOR]

Objectives: To compare temporal and pressure values between racewalking and normal walking (freely selected speed) and evaluate the impact of racewalking on normal walking. Design and Participants: Temporal and plantar-pressure values were recorded (xPression system) during normal walking and racewalking in 8 high-level racewalkers. The Wilcoxon test was used for comparisons. Measurements: Duration of walking and racewalking cycle phases (seconds and percentage of the cycle), peak and average pressures under the hind foot and metatarsal heads, and pressure distribution (%) among metatarsal heads. Results and Conclusions: Normal walking: temporal parameters similar to those described in normal gait; peak pressures higher than those described in nonracewalkers with displacement toward lateral forefoot. Racewalking: shorter cycles (important decrease of midstance phase); higher peak pressures than during normal walking in the hind foot and 4th and 5th metatarsal heads; average pressures similar to normal walking in hind foot and lower in forefoot; pressure displacement toward lateral forefoot greater than in normal walking. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the kinetics of the walk-to-run transition (WRT) and run-to-walk transition (RWT), when accelerating or decelerating across transition speed (a = 0.17 m·s-2). Nine women performed gait transitions on a 50-m-long walkway. Vertical ground reaction forces (GRFs) and the center of pressure (COP) were examined in the range from 3 steps before to 3 steps after transition in order to identify the possible occurrence of a transition process, in order to facilitate the actual realization of transition. The actual transition is realized in one step, during WRT and RWT. This transition step was characterized by an outlying vertical GRF and COP trajectory (deviating from walking and running). Despite this clear discontinuity, a transitional adaptation period (process) appeared in both transitions. In the WRT, transition was prepared and kinetic adaptations were found in the last step before transition. The RWT was pre- and "post"-pared and only completed during the first walking step after transition. Thus, the WRT and RWT are two distinct phenomena, with different kinetics. [ABSTRACT FROM AUTHOR]

There is a need for greater understanding of setting-specific influences on physical activity to complement the predominant research paradigm of individual-centered influences on physical activity. In this study, the authors used a cross-sectional multilevel analysis to examine a range of neighborhoodlevel characteristics and the extent to which they were associated with variation in self-reported physical activity among older adults. The sample consisted of 582 community-dwelling residents age 65 years and older (M = 73.99 years, SD = 6.25) recruited from 56 neighborhoods in Portland, OR. Information collected from participants and neighborhood data from objective sources formed a two-level data structure. These hierarchical data (i.e., individuals nested within neighborhoods) were subjected to multilevel structural-equation-modeling analyses. Results showed that neighborhood social cohesion, in conjunction with other neighborhood-level factors, was significantly associated with increased levels of neighborhood physical activity. Overall, neighborhood-level variables jointly accounted for a substantial variation in neighborhood physical activity when controlling for individual-level variables. [ABSTRACT FROM AUTHOR]

Presents several articles on exercise therapy for older adults. Resistance training as a model for rehabilitating patients with peripheral arterial disease; Effects of intense strength training on functional tests in older adults; An evaluation of three self-report physical activity instruments for older adults.

This study examined the effect of a physical activity program on student activity during recess and on disruptive classroom behavior. The program was implemented during recess for 5 weeks in a rural elementary school. Prior to and during the program, teachers recorded observations of sedentary students during recess and of disruptive classroom behavior before and after recess. The number of sedentary students during recess decreased significantly during the program (p < .05) and classroom behavior significantly improved after recess (p < .001), differences that were not seen prior to the start of the program. Physical activity initiatives can improve student participation in physical activity during recess while costing little and maintaining student choice. Increased physical activity during recess improves children's ability to meet daily activity recommendations and may improve the classroom environment by decreasing disruptive behaviors. [ABSTRACT FROM AUTHOR]

Purpose: The short-term restriction of carbohydrate (CHO) can potentially influence iron regulation via modification of postexercise interleukin-6 (IL-6) and hepcidin levels. This study examined the effect of a chronic ketogenic low-CHO high-fat (LCHF) diet on iron status and iron-regulatory markers in elite athletes. Methods: International-level race walkers (n = 50) were allocated to one of three dietary interventions: (i) a high-CHO diet (n = 16), (ii) a periodized CHO availability (n = 17), or (iii) an LCHF diet (n = 17) while completing a periodized training program for 3 wk. A 19- to 25-km race walking test protocol was completed at baseline and after adaptation, and changes in serum ferritin, IL-6, and hepcidin concentrations were measured. Results from high-CHO and periodized CHO were combined into one group (CHO; n = 33) for analysis. Results: The decrease in serum ferritin across the intervention period was substantially greater in the CHO group (37%) compared with the LCHF (23%) group (P = 0.021). After dietary intervention, the postexercise increase in IL-6 was greater in LCHF (13.6-fold increase; 95% confidence interval [CI] = 7.1–21.4) than athletes adhering to a CHO-rich diet (7.6-fold increase; 95% CI = 5.5–10.2; P = 0.033). Although no significant differences occurred between diets, CI values indicate that 3 h postexercise hepcidin concentrations were lower after dietary intervention compared with baseline in CHO (β = −4.3; 95% CI = −6.6 to −2.0), with no differences evident in LCHF. Conclusion: Athletes who adhered to a CHO-rich diet experienced favorable changes to the postexercise IL-6 and hepcidin response, relative to the LCHF group. Lower serum ferritin after 3 wk of additional dietary CHO might reflect a larger more adaptive hematological response to training. [ABSTRACT FROM AUTHOR]

Walking plays an important role in human daily life. Many previous studies suggested that long-term walking training can modulate brain functions. However, due to the use of measuring techniques such as fMRI and PET, which are highly motion-sensitive, it is difficult to record individual brain activities during the movement. This pilot study used functional near-infrared spectroscopy (fNIRS) to measure the hemodynamic responses in the frontal-parietal cortex of four elite race walkers (experimental group, EG) and twenty college students (control group, CG) during tasks involving action observation, motor imagery, and motor execution. The results showed that activation levels of the pars triangularis of the inferior frontal gyrus (IFG), dorsolateral prefrontal cortex (DLPFC), premotor and supplementary motor cortex (PMC and SMC), and primary somatosensory cortex (S1) in the EG were significantly lower than in the CG during motor execution and observation tasks. And primary motor cortex (M1) of EG in motor execution task was significantly lower than its in CG. During the motor imagery task, activation intensities of the DLPFC, PMC and SMC, and M1 in the EG were significantly higher than in the CG. These findings suggested that the results of motor execution and observation tasks might support the brain efficiency hypothesis, and the related brain regions strengthened the efficiency of neural function, but the results in motor imagery tasks could be attributed to the internal forward model of elite race walkers, which showed a trend opposed to the brain efficiency hypothesis. Additionally, the activation intensities of the pars triangularis and PMC and SMC decreased with the passage of time in the motor execution and imagery tasks, whereas during the action observation task, no significant differences in these regions were found. This reflected differences of the internal processing among the tasks. [ABSTRACT FROM AUTHOR]

This study examined the effects of attentional focus on race walking performance. Sixteen experienced race walkers, eight males and eight females, were randomly assigned to walk four separate half-mile segments on a quarter-mile track under specific sets of instructions. Two sets of instructions were externally oriented and two were internally oriented. The internally oriented instructions included a set asking the subjects to focus on cadence (the number of steps taken in a designated period of time) and a set asking them to focus on stride length (the distance covered in a single step). The externally oriented instructions asked subjects to use a dissociative strategy. Although no overall difference was found between internal and external focus, results indicated that the focus on cadence was superior to both the external focus, p<.05, and a focus on stride length, p<.05. No significant differences between the stride length focus and the external focus were found. These results are discussed in terms of the importance of using an internal focus that is beneficial. [ABSTRACT FROM AUTHOR]

Objectives Past studies have concluded that racing games may induce car drivers' risk-taking behaviours. Limited research has been conducted to investigate whether such an effect applies to pedestrians when crossing a street. This study investigates the effects of smartphone racing games on pedestrian's risk-taking inclinations. Materials and Methods Using WiFi video cameras, pedestrians’ risk-taking inclinations such as game playing when crossing the street, red-light violation, and walking outside the crosswalk at a signalised intersection in Taipei City were observed. Data such as their phone features, smartphone game types, and personal attributes were obtained in the interviews conducted after pedestrians had completed crossing the street. Effects of racing games (RCG) were compared with those of several other games (e.g., Pokemon, RPG: Role-Playing Game, ACT: Action Game, SPG: Sports Game, FTG: Fighting Game, STG: Shooting Game, PZG: Puzzle Game, ETC: Other Game). Results A total of 1480 participants completed crossing the street and were interviewed between April 2017∼March 2018. Pokemon Go was most associated with game playing when crossing, running the red light, and walking outside the crosswalk. Logistic regression models reveal several other important determinants of risk-taking inclinations: being a student, larger smartphone screen size, unlimited Internet allowance. Student players of Pokemon GO, and playing Pokemon with unlimited Internet allowance, appear to contribute to pedestrian's risk-taking inclinations. Conclusions RCG appears not to be associated with pedestrian's risk-taking behaviours as much as Pokemon Go does. Instead, compared to other smartphone games, Pokemon Go is most associated with pedestrian's risk-taking inclinations. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers. Methods: Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km⋅h-1, where race walking economy (ml⋅kg-1⋅km-1) and spatiotemporal gait variables were analysed at different speeds. Results: 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p < 0.001). Longer ground contact times, shorter flight times, longer midstance sub-phase and shorter propulsive sub-phase during stance were related to a better race walking economy (moderate effect, p < 0.05). Conclusion: According to the results of this study, the fastest race walkers were more economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of an acute 24-h nitrate-rich beetroot juice supplement (BR) on the energy cost, exercise efficiency and blood pressure responses to intermittent walking at different gradients.Methods: In a double-blind, cross-over design, eight participants were provided with a total of 350 ml of nitrate-rich (~ 20.5 mmol nitrate) BR or placebo (PLA) across 24 h before completing intermittent walking at 3 km/h on treadmill at gradients of 1, 5, 10, 15 and 20%.Results: Resting mean arterial pressure (MAP) was ~ 4.1% lower after BR (93 vs. 89 mmHg; P = 0.001), as well as during exercise (102 vs. 99 mmHg; P = 0.011) and recovery (97 vs. 94 mmHg; P = 0.001). Exercising (1227 vs. 1129 ml/min P < 0.001) and end-stage (1404 vs. 1249 ml/min; P = 0.002) oxygen uptake ([Formula: see text]O2) was lower in BR compared to PLA, which was accompanied by an average reduction in phase II [Formula: see text]O2 amplitude (1067 vs. 940 ml/min; P = 0.025). Similarly, recovery [Formula: see text]O2 (509 vs. 458 ml/min; P = 0.001) was lower in BR. Whole blood potassium concentration increased from pre-post exercise in PLA (4.1 ± 0.3 vs. 4.5 ± 0.3 mmol/L; P = 0.013) but not BR (4.1 ± 0.31 vs. 4.3 ± 0.2 mmol/L; P = 0.188).Conclusions: Energy cost of exercise, recovery of [Formula: see text]O2, MAP and blood markers were ameliorated after BR. Previously-reported mechanisms explain these findings, which are more noticeable during less-efficient walking at steep gradients (15-20%). These findings have practical implications for hill-walkers. [ABSTRACT FROM AUTHOR]

Race walking is an event where the knee must be straightened from first contact with the ground until midstance. The aim of this study was to compare knee angle measurements between 2D videography and 3D optoelectronic systems. Passive retroreflective markers were placed on the right leg of 12 race walkers and 3D marker coordinate data captured (250 Hz), with 2D video data (100 Hz) recorded simultaneously. Knee angle data were first derived based on the markers' coordinates, and separately by using a 3D model that also incorporated thigh and shank clusters; the video data were analysed using both automatic tracking and manual digitising, creating four conditions overall. Differences were calculated between conditions for stance (using root mean square values), and at discrete events. There were few differences between systems, although the 3D model produced larger angles at midstance than using automatic tracking and marker coordinates (by 3 - 6°, P < 0.05). These differences might have occurred because of how the 3D model locates the hip joint, and because of the addition of marker clusters. 2D videography gave similar results to the 3D model when using manual digitising, as it allowed for errors caused by skin movement to be corrected. [ABSTRACT FROM AUTHOR]

The aim of the study was to measure the influence of bent knee and loss of contact warnings on lap speed in race walkers and correlate with maximum and minimum lap speeds. Fifty-four national race walkers (32 men and 22 women, 22.8 ± 9.0 and 20.7 ± 9.0 years old, respectively) participated in the study. The lap speed pre-warnings, at the moment and post-warnings were compared, with analysis between bent knee and loss of contact. Additionally, the maximum and minimum lap speeds were associated with the lap speed at the moment of warning compared between bent knee and loss of contact. The bent knee warnings were given at lower speeds than loss of contact warnings (F(1) = 22.894, p = 0.001). Additionally, only bent knee warnings negatively influenced the athlete’s speed (F(2) = 11.430, p = 0.001) and were associated with the minimum or maximum lap speed in the race (r = 0.440, p = 0.001; r = 0.201, p = 0.036, respectively). In conclusion, these findings showed that athletes should avoid very fast or very slow speeds, which reduce the risk of receiving bent knee warnings, and consequently, speed throughout the race. [ABSTRACT FROM AUTHOR]

Objective. Barefoot technology shoes are becoming increasingly popular, yet modifications are still needed. The present study aims to gain valuable insights by comparing barefoot walking to neutral shoe walking in a healthy youth population. Methods. 28 healthy university students (22 females and 6 males) were recruited to walk on a 10-meter walkway both barefoot and in neutral running shoes at their comfortable walking speed. Full step cycle kinematic and kinetic data were collected using an 8-camera motion capture system. Results. In the early stance phase, the knee extension moment (MK1), the first peak absorbed joint power at the knee joint (PK1), and the flexion angle of knee/dorsiflexion angle of the ankle were significantly reduced when walking in neutral running shoes. However, in the late stance, barefoot walking resulted in decreased hip joint flexion moment (MH2), second peak extension knee moment (MK3), hip flexors absorbed power (PH2), hip flexors generated power (PH3), second peak absorbed power by knee flexors (PK2), and second peak anterior-posterior component of joint force at the hip (APFH2), knee (APFK2), and ankle (APFA2). Conclusions. These results indicate that it should be cautious to discard conventional elements from future running shoe designs and rush to embrace the barefoot technology fashion. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse gait variability and symmetry in race walkers. Eighteen senior and 17 junior athletes race walked on an instrumented treadmill (for 10 km and 5 km, respectively) at speeds equivalent to 103% of season’s best time for 20 km and 10 km, respectively. Spatio-temporal and ground reaction force (GRF) data were recorded at 2.5 km, and at 4.5, 6.5 and 8.5 km for a subsection of athletes. Gait variability was measured using median absolute deviation (MAD) whereas inter-leg symmetry was measured using the symmetry angle. Both groups showed low variability for step length (<0.9%), step frequency (<1.1%), contact time (≤1.2%) and vertical peak force values (<5%), and neither variability nor symmetry changed with distance walked. Junior athletes were more variable for both step length (P = 0.004) and loading force (P = 0.003); no differences for gait symmetry were found. Whereas there was little mean asymmetry overall, individual analyses identified asymmetry in several athletes (symmetry angle ≥ 1.2%). Importantly, asymmetrical step lengths were found in 12 athletes and could result from underlying imbalances. Coaches are advised to observe athletes on an individual basis to monitor for both variability and asymmetry. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse lower limb work patterns in world-class race walkers. Seventeen male and female athletes race walked at competitive pace. Ground reaction forces (1000 Hz) and highspeed videos (100 Hz) were recorded and normalised joint moments, work and power, stride length, stride frequency and speed estimated. The hip flexors and extensors were the main generators of energy (24.5 J (±6.9) and 40.3 J (±8.3), respectively), with the ankle plantarflexors (16.3 J (±4.3)) contributing to the energy generated during late stance. The knee generated little energy but performed considerable negative work during swing (-49.1 J (±8.7)); the energy absorbed by the knee extensors was associated with smaller changes in velocity during stance (r = .783, P < .001), as was the energy generated by the hip flexors (r = -.689, P = .002). The knee flexors did most negative work (-38.6 J (±5.8)) and the frequent injuries to the hamstrings are probably due to this considerable negative work. Coaches should note the important contributions of the hip and ankle muscles to energy generation and the need to develop knee flexor strength in reducing the risk of injury. [ABSTRACT FROM AUTHOR]

Key points Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support., Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole-body fat oxidation during exercise in race walkers over a range of exercise intensities., The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real-life race performance in elite race walkers., In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity., Abstract We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world-class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg−1 day−1: 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day−1 CHO; 78% energy as fat; 2.1 g kg−1 day−1 protein; LCHF, n = 10). Post-intervention [ABSTRACT FROM AUTHOR]

Combining advances from gait analysis and motor learning fields, this study aims to examine invariant characteristics and practice-related changes in the control of walking gait when learning a biomechanically constrained pattern, racewalking (RW). RW's regulation imposes a straightened knee at the stance phase which differentiates it qualitatively from normal walking. Using 3D motion analysis, we computed key kinematic variables from a whole-body model. Principal component analysis was then used as a tool to evaluate the evolution of normal walking synergies (S0) immediately at the first practice session (S1) and further with practice (S1-S4). Before the start of practice, normal walking was characterized by two predominant control dimensions explaining an upper-extremities/antero-posterior component (PC1) and a lower-extremities/vertical component (PC2). Compared to normal walking, the immediate increase at S1 in the number of PCs needed to explain a significant portion of movement variance could be suggestive of a recruitment of a task-specific component. With practice, the significant decrease in the variance accounted for by PC1 and in the correlations between many variables could indicate a destabilization of spontaneous tendencies to facilitate the adoption of more task-specific coordinative pattern. PC2 seemed to be reinforced with practice where a significant increase in its explained variance was observed. In sum, this study shows that common features in the gait control are preserved with practice, and the movement reorganization, however, seems rather defined by shifts in the relative contribution of some variables within each PC. [ABSTRACT FROM AUTHOR]